07:51am Monday 13 July 2020

Horrors of war harden group alliances

War is hell, and according to new research, experiencing its horrors can cause people to have a greater affinity for members of their own group, particularly if they are exposed to warfare in early adulthood or later in childhood.

“These effects have the potential to explain why conflict sometimes leads to cycles of war and sometimes stimulates nation-building in its wake,” says study co-author Joseph Henrich of the University of British Columbia. The research appears in the journal Psychological Science.

Researchers conducted the study in the war-torn nations of Georgia and Sierra Leone. They had participants play games in which they had to choose how to allocate tokens to themselves and an anonymous partner. In some cases, the anonymous partner was from the same village or school. In other cases, the partner was from a distant village or different school.

Those who had experienced war were more willing to sacrifice to reduce inequality if their partner was from the same village or school.
Joe Henrich

Joe Henrich

No such effects were present in participants younger than six or older than 20 when they experienced war. “These findings suggest that if war is experienced during a sensitive window in development between middle childhood and early adulthood, then it leaves an enduring mark,” says co-author Michal Bauer of Charles University, Czech Republic.

The research may help to explain why war can lead to nation building or a perpetual cycle of war. “When people identify with an in-group that coincides with the state or nation, then nation-building can be enhanced,” says Henrich, a professor in UBC’s Depts. of Psychology and Economics. “For people who identify with a subnational identity, such as an ethnic group, war can sow the seeds of future conflicts.”


The researchers collected data from 543 children in the Republic of Georgia following the brief but devastating war between Russia and Georgia over South Ossetia. They also collected data from 586 adults in Sierra Leone following an 11-year civil war that ended in 2002, which led to the displacement of much of the population and the deaths of over 50,000 civilians.

Based on evolutionary theory, the researchers hypothesized that experiences with intergroup conflicts should lead individuals to become more focused on their own group’s wellbeing, since individual survival is often linked to the fate of the group. Recruiting participants who had actually experienced war allowed the researchers to study human nature in the context of real-world conflicts.

“Our research shows that exposure to war affects human psychology in specific ways,” says Bauer. “These ‘war effects’ emerge in the short-term and, importantly, they have long-term impact on psychology if war is experienced during middle childhood and adolescence.”

In addition to Henrich and Bauer, co-authors include Alessandra Cassar of the University of San Francisco and Julie Chytilová of Charles University. Henrich is UBC’s Canada Research Chair in Culture, Cognition and Evolution.

For a copy of the article “War’s Enduring Effects on the Development of Egalitarian Motivations and In-Group Biases,” please contact Lucy Hyde at 202-293-9300 or [email protected] The research was supported by the Canadian Institute for Advanced Research and the Czech Science Foundation.

Find other stories about: Armistice Day, conflict, Dept. of Psychology, Joe Henrich, Psychology, Remembrance Day, Veterans’ Day, War

Basil Waugh
UBC Public Affairs
Tel: 604.822.2048
Email: [email protected]

Prof. Joe Henrich
UBC Dept. of Psychology
Email: [email protected]

Lucy Hyde
Association for Psychological Science
Tel: 202.293.9300
Email: [email protected]

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